HEMODYNAMICS

Question 1

poiseuille equation

Answer 1

• relationship of flow, pressure and resistance

- single vessel, organ

Question 2

poiseuille equation

Answer 2

• flow= to pressure gradient/resistance
• P1 upstream pressure
• P2 pressure at the end of segment/circuit
• R resistance of vessel bet. P1 and P2

Question 3

resistance is inverse to

Answer 3

• flow

- radius

Question 4

the most important factor determining resistance of a vessel

Answer 4

• vessel radius

Question 5

resistance is proportional ….

to but inversely proportional to flow

Answer 5

• viscosity
• polycythemia vera (increase viscosity and resistance, decrease flow leading to thrombosis)
• anemia (decrease viscosity and resistance, increase flow hyper dynamic flow fast rush of blood bruit)

Question 6

50% occlusion of the left anterior descending artery

Answer 6

• 16x decrease in flow (r4)

Question 7

polycythemia vera

Answer 7

increase viscosity and resistance,
decrease flow leading to thrombosis
an increase in hematocrit, increase in viscosity

Question 8

turbulent flow

Answer 8

• murmurs
• bruits
• severe stenosis
• more resistance
• > 2000 flow

Question 9

laminar flow

Answer 9

• least resistance
• good flow
• ## away from the wall towards the vessel

Question 10

reynolds number

Answer 10

• diameter x velocity x density/ viscosity

Question 11

resistance

Answer 11

series

parallel

Question 12

series

Answer 12

• flow is dependent flow must be equal at all points
• resistance to the total series is equal to the sum of individual system
• equal flow
• Rt > Ri
• with in organs

Question 13

parallel

Answer 13

• flow is independent to each other
• flow is not equal
• Rt

Question 14

the total resistance(Rt) is always

Answer 14

• less than any of the individual resistance (Ri)

Question 15

organ donor (Kidney) parallel

Answer 15

• as we add total becomes less
• subtract resistances the total resistance increase
• increase resistance
• flow is decrease
• CO decrease to compensate for increase BP
• HR decrease to decrease BP
• bradycardia normal for donor
• wt gain
• increase TPR, MAP

Question 16

CO

Answer 16

= mean arterial pressure/TPR

Question 17

mean arterial pressure

Answer 17

= CO x TPR

Question 18

CO

Answer 18

= HR x SV

Question 19

LaPlace relationship (wall tension)

Answer 19

• T- wall tension
• P- pressure
• r- radius
• dysfunction can lead to aneurysm

Question 20

aorta

Answer 20

• is the artery with the greatest wall tension (greatest pressure while lying down and RADIUS)
• reason for aorta predispose to aneurysm
• causing dissecting aneurysm

Question 21

increase in radius and pressure

Answer 21

• increase in tension agains the wall

- increase pooling of blood causing less blood goes to the heart

Question 22

compliance

Answer 22

• change in volume/ change in pressure
• vessel is easily stretched
• 60 y/o has more compliance in his lung
• aging loose elasticity

Question 23

elasticity

Answer 23

• inverse to compliance
• recoil
• more elasticity less compliance

Question 24

VEINS

Answer 24

• 20x more compliant than arteries
• 70% of systemic blood volume
• major blood reservoir
• less elasticity(to have more compliance, has the ability to change volume) due to less muscles in the walls
• no recoil
• small change in pressure will cause a large change in volume
• have high compliance

Question 25

veins pathophysiology

Answer 25

- in hemorrhage - venous pressure decreases - causing passive constriction of veins - decrease blood storage - blood is removed from the vein to the arteries to increase CO to compensate to hemorrhage - SYMPATHETIC INNERVATION causing VASOCONTRICTION alpha 1

Question 26

artery

Answer 26

- decrease in compliance | - increase radius increase flow

Question 27

venodilator (nitrates)

Answer 27

- decrease in venous return - decrease preload - decrease flow

Question 28

arteriolar dilator

Answer 28

- increase flow - decrease in pressure in the system - decrease TPR arteries

Question 29

volume loading

Answer 29

- increase venous pressure which causes passive dissension of veins

Question 30

hemorrhage affected VEINS

Answer 30

- decrease volume - decrease pressure - sympathetic response - alpha 1 - constriction - decrease pooling

Question 31

fluid infusion, fluid overload

Answer 31

- increase pressure - increase pooling of blood - by distention of the vein - less blood will go to the heart - decreasing the venous return in the heart - will cause massive dilation of the veins